Endothelin-1 increases arterial sensitivity to 5-hydroxytryptamine.
Rings of rabbit abdominal aorta were pretreated with endothelin-1 (ET-1) or vehicle and then isometric contractions to cumulative additions of 5-hydroxytryptamine (5-HT) were recorded. ET-1 at concentrations of 0.4, 1 and 2 nM produced contractions of 7, 15 and 35% of maximal potassium chloride-induced contractions, respectively. Pretreatment of aortic rings with these concentrations of ET-1 increased (P less than 0.01) arterial sensitivity (EC50) to 5-HT 1.9-, 2.4- and 3.5-fold, respectively, without affecting peak 5-HT-induced force. Acetylcholine-induced, endothelium-dependent aortic relaxations were not affected by pretreatment with ET-1-pretreated but not untreated aortic rings. These results suggest that ET-1 could promote arterial vasospasm by sensitizing the artery to 5-HT released from platelets.
Consigny
P M
PM
Department of Radiology, Thomas Jefferson University Hospital, Philadelphia, PA 19107.
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001012:Aorta, Abdominal / Q000187:drug effects; D016232:Endothelins / Q000494:pharmacology*; D066298:In Vitro Techniques; D007537:Isometric Contraction; D009119:Muscle Contraction / Q000187:drug effects; D009126:Muscle Relaxation / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D011189:Potassium Chloride / Q000494:pharmacology; D011817:Rabbits; D012701:Serotonin / Q000494:pharmacology*; D013552:Swine
D016232:Endothelins; D012701:Serotonin; D011189:Potassium Chloride; D000109:Acetylcholine